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Altamira, cave 30 km (19 mi) west of Santander, in northern Spain, whose walls bear paintings and engravings�chiefly of bison, deer, horses, and boar�dating from the Stone Age. Altamira has been called �the Sistine Chapel of Prehistory� and, with Lascaux, it is one of the most important prehistoric painted caves known to date (see Palaeolithic Art). The paintings were discovered in 1879, but experts initially dismissed them as forgeries, and it was not until the turn of the century that they were accepted as genuine.
In the meandering interior of the cave, 270 m (890 ft) long, at least 930 painted or engraved figures of animals have been identified. The most spectacular group of paintings is that which covers the ceiling of a chamber near the entrance: it is a tightly packed and homogeneous cluster of bison and other animals depicted in red, black, mauve, and other earth colours. These polychrome paintings, covering an area approximately 18 m (59 ft) long by 9 m (almost 30 ft) wide, are in fact superimposed on four earlier layers of decoration which, in chronological order, consist of continuous-line engravings, paintings in red, multiple-trace engravings, and paintings in black. Other motifs found in the cave consist of human figures, hand-prints, finger-tracings made in the soft layer of clay coating the rock, and various non-figurative motifs.
Excavation in the cave revealed various pigments and implements, the bones of bison, stags, and horses, and the skeleton of a cave bear. Radiocarbon testing on the charcoal used to depict the bison on the painted ceiling has given dates ranging from 12,380 BC to 11,620 BC. It is thought likely, however, that the cave was used continuously from the Solutrean Period (which began c. 19,000 BC) to the late Magdalenian (which ended c. 11,000 BC).